Some power machines including skid steer loaders, tracked loaders, steerable axle loaders, excavators, telehandlers, walk behind loaders, trenchers, and the like, employ engine powered hydraulic or hydrostatic drive systems. Some of these power machines have employed electronic drive control systems for controlling their hydrostatic drive systems. Drive control systems typically include operator input devices that are capable of being manipulated by an operator to provide signals that indicate a drive control intention. Signals from the operator input devices are provided to one or more actuation devices that are capable of varying the displacement of one or more hydrostatic pumps in the hydrostatic drive system. Hydraulic and hydrostatic drive systems create large power loads on a power source, particularly when a power machine is engaged in, for example, digging or load carrying operations. Excessive power loads on a power source such as an engine—loads that can be created by drive systems and other function systems on a power machine—can result in reduced efficiency and performance, including the potential that excessive loads may cause the engine to stall. It is known that a particular engine performs most efficiently at a given percentage of its maximum torque output. It is desirable to maintain operation of the engine at or near that target torque output.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.